Gregor Mendel used pea plants that were heterozygous for each of two traits—seed color and seed shape—to generate a dihybrid cross. The phenotypic ratio of the resulting offspring was nine with round and yellow seeds, three with round and green seeds, three with wrinkled and yellow seeds, and one with wrinkled and green seeds. From these results, what could Mendel conclude?
Traits are inherited as pairs, sets, or groups.
Traits that are dominant mask traits that are recessive.
Gametes carry one allele for each trait.
Traits are passed independently of one another.